Screening machine



Sept. 1, 1942. J. A. COYLEIETAL SCREENING MACHINE Filed July 17, 1941 2Sheets-Sheet 1.

E2 Z? i% Sept; 1942- J. A. COYLE'ETAL 2,294,448

SCREENING MACHINE Filed July 1'7, 1941 2 Sheets-Sheet 2 jifyeizz aiwJIQD/YA. (by/e 672a2 /9M 19f Roi/z Patented Sept. 1, 1942 OFFICESCREENING MACHINE Joseph A. Coyle and Charles H. Roth,

Minneapolis, Minn.

Application July 1'7, 1941, Serial No. 402,754

1 Claim.

Our invention provides an improved screenin machine or device and,generally stated, consists of the novel devices, combinations ofdevices, and arrangement of parts hereinafter described and defined inthe claims.

The screening machine is capable of a large range of uses but we havehad particularly in mind and have especially designed the same for theseparation of materials such as gravel, crushed stone, coal and thelike.

The chief feature of this invention is found in an improved off and onbalance vibrator head which will be fully described in connection withthe accompanying drawings.

Referring to the drawings, wherein like characters indicate like partsthroughout the several views.

-Fig. 1 is a vertical longitudinal section taken centrally through ascreening machine or device designed in accordance with what is at thepresent considered the preferred commercial form thereof;

Fig. 2 is a transverse section taken on the line 2-2 of Fig. 1;

Fig. 3 is a section taken on the line 33 of Fig. 4 is a view inperspective showing the relatively adjustable wheel-like elements of thevibrator head laterally separated and turned, the one away from theother.

Fig. 5 is a fragmentary view showing the central portion of one of thesupporting springs; and

Fig. 6 is a fragmentary section taken on the line 66 of Fig. 1.

In Figs. 1 and 2 of the drawings the numeral l indicates a firmlysupported relatively stationary rectangular main frame or base supportwhich, in practice, will be mounted for adjustments into differentpositions of inclination and will be firmly supported in position inwhich it may be set by well-known or any suitable means foraccomplishing such support and adjustment. At its intermediate portionand approximately at the point where it would usually be pivotallysupported, the side bars of said frame I0 is provided with hangerbrackets II to which, by means of bolt-equipped clamping devices l2, theintermediate portions of leaf springs l3 are rigidly connected. Thesesprings l3 may be and preferably are of the semi-elliptical type made upof a plurality of leaves bound together by clips M or the like.

The screen or sieve I is preferably a woven wire structure of the propermesh for the particular kind of separation to be made and it is mountedin a hopper-like frame or shoe [6, the bottom of which is open but, asshown, is provided with transverse cross, bars I! preferably V-shaped incross section with their upper edges engaging and supporting the screenl5.

Either by tilting the frame I0 or otherwise, the shoe I6 will be setwith its screen I5 inclining toward the open end of the shoe; and inpractice, the said shoe and screen will usually be set at a, greaterinclination than shown in Fig. 1.

To support the shoe and screen for up and down vibratory movementsperpendicular to the plane of the screen while holding the same againstendwise vibrations or vibrations in the direction of the flow of thecoarser materials over the screen, the springs I3, at their front ends,are pivoted to lugs or brackets l8 that are rigidly secured to thebottom of the sides of the shoe I6; and at their other or rear ends, thesprings 13 are connected by links I9 to the rear portion of the sides ofsaid shoe Hi. This arrangement is highly important for reasons that willbe more fully described later on; but it is desirable at this point tocall attention to the fact that under the inclination of the shoe andscreen just noted, the weight of the load carried by the springs willtend to and will nearly or quite straighten said springs, and will putthe forwardly projecting portions, to wit: the portions at the left ofthe hanger brackets I I, under tension.

The screen I5 can be attached or anchored to the shoe by any suitablemeans but in the drawings it is shown as attached at its edges to thesides of the shoe by means of clamping strips 20 and co-operatingnut-equipped bolts 2|.

As already indicated, vibratory movement of the shoe and screen will beproduced by so-called vibrator heads made up of co-operating elementsthat are adjustable to vary the vibratory action from zero to a certainmaximum. Preferably, and as shown in the drawings, there are two ofthese vibrator heads mounted on a transverse shaft 22 journaled insuitable bear ngs, preferably roller or ball bearing devices 23, appliedon the upper side portions of the shoe I6. This shaft 22 is shown asprovided with a pulley 24 over which a power-driven belt, not shown, isadapted to run t impart rotary movement to said shaft 22. Of course,said shaft 22 can be power-driven by any other suitable means.

The vibrator heads involve novel and important features; and eachinvolves two wheel-like elements 25 and 26. Wheel 26 has aconcentrically located hub 21 that is formed with a quite deep annularor endless groove 28. Hub 21, by a key 29 or the like, is keyed. toshaft 22, all as best shown in Figs. 3 and 4. Wheel 25 has a concentrichole or bore 30 that snugly fits and is adapted to be telescoped ontothe hub 21 of wheel 26. Wheel 25 has a segmental cavity 3| and wheel 26has a Similar segmental cavity 32. The cavities 3! and 32 are preferablyof the same extent and give each member of the head the samepreponderance of weight on one side of diameters thereof, so that whenthe two wheels are assembled, as shown in Fig. 3, the vibrator headswill be adapted for any desired degree of off balance action. When thetwo wheels '25 and 26 are adjusted so that their cavities 32 arediametrically opposite, the heavier portions of the said wheels willalso be at diametrically opposite points and the head, when revolved,will, therefore, be balanced and will run at high speed or at any speedwithout tending to produce vibration of the screen or shoe.

It is also important'that the perimeter of the vibrator head made up ofthe two assembled wheels will not only be concentric to the axis ofrotation but smooth and free from projections which will not tend tothrow or project rocks, lumps of coal and the like that may accidentallycome in contact therewith. In actual practice it has been found thatdevices rotating at high speeds that have irregular or projectingportions, which would catch and. project objects, are liable to projectsuch articles at high speeds and injure attendants or do other damage.

The wheel 25 is adapted to be easily telescoped onto the hub 21 providedthe periphery of said hub has not been upset, distorted or in any waymade irregular. Hence, as the means for securing the wheel 25 on saidhub and while permitting infinitesimal fine adjustment of the balanceoffsetting action of the two members, wheel 25 is provided with adiametrically adjustable screw 33 and the hub 21 is provided with theabove noted deep annular groove or channel 28. The reduced end 34 ofscrew 33 is projected into the channel 28 and engages only with thebottom of said groove or channel and under no condition can mar or upsetthe smooth exterior of the hub 27. When the screw 33 is thus applied, itis evident that wheel 25 can not move axially on the hub 21 but thatsaid wheel 25 is free for rotary adjustments in respect to the wheel 26.Here it may be noted that wheel 26 is further secured to shaft 22 by aset-screw 35.

At a means for determining when the vibrator heads are set for apredetermined desired vibratory action, the peripheries of the wheels'25 and 26 are graduated. When the graduation marks are set at zero thevibrator heads will be balanced and there will be no tendency to producevibration in the rotation thereof; and, of course, these graduationswill indicate, by the amount they are set from zero, the amount ofvibratory action there will be produced up to the point of maximumaction.

Summary of operation The manner in which vibrations of screen or sievestructures of the general character above described is produced is wellunderstood. Of course, the off balance vibrator heads or devices shouldbe mounted on the screen structure or assembly and, under rotation ofthe vibrator device or devices, when set away from zero or neutral,force will be produced that would tend to impart a gyratory or rotarymovement in a vertical plane. However, with the spring suspension of thearrangement described, the sup porting springs l3 hold a screenstructure against movements in a horizontal direction or in the generaldirection of the plane of the screen, but resiliently support the screenfor up and down movements in a direction perpendicular to the screensurface. In the described structure, both ends of the springs act tosupport the screen structure, but only those ends of the springs thatare directly pivoted to the screen structure or rigid projectionsthereof, resist horizontal or ap- "proximately horizontal vibratorymovements of the screen. The links I9, at th other ends of the springs,simply act as horizontal yielding supporting connections between thesprings and screen structure.

It is now important to note the importance of connecting those portionsof the springs that are normally under tension directly or pivotally tothe screen structure or assembly. As already stated, due to theinclination of the screen structure, it is only those forwardlyprojecting half portions of the springs that project, for example, fromright to left from the supporting brackets or hangers II that are thusput under normal tension, and that the oppositely projecting or rearportions of said springs are not at any time put under compression.

It is of the utmost importance that the springs be pivotally or directlyconnected to the screen structure or assembly only at one end. Moreover,it has, in practice, been found highly important that only thoseportions of the springs that are under tension be arranged to resisthorizontal vibrations and used to hold the sieve structure for up anddown movements perpendicular to the screen surface. With a reversearrangement, to wit: with a direct pivotal connection between the screenstructure and the rear end or ends of the springs that are tensioned, itwas found that the vertically produced major vibrations transmittedthrough the tensioned portions of the springs, would set up harmonic orminor vibrations in said tensioned spring portions which would interferewith, and in many instances, especially under high speeds,neutralize orsubstantially destroy the major and intended vertical vibratorymovements of the screen. Such defects in the operation have, inpractice, been entirely overcome by the arrangement wherein, as abovedescribed, the control of the major screen vibrations is taken throughthe tensioned portions of the springs.

It is well understood that the desired vibrations are those that willimpart the vertical vibrations only to the screen in an up and downdirection as nearly as possible perpendicular to the screen surfacethereby, in the most direct possible way, causing the fine particles topass directly downward through the screen while relying for travel ofthe coarser materials over the screen under the action of gravity.

As already stated, the so call'ed semi-eliptical spring will be nearlyor quite straight or flat under load, so that the pivoted ends of thetensioned portions of the springs will be caused to move on straightlines or in slight deviation from perfectly true lines perpendicular tothe axis of the screen will be negligible.

In the preferred arrangement the off balance vibratory means involves apair of the heads described located one near each side of the screenassembly and also in the preferred arrangement, the resilient supportingmeans involves two of the said springs located one at each side of themachine.

The claim of this application is directed to a modification in thenature of an improvement on the vibrator head for screening devicesdisclosed and claimed in our prior application filed of date January2'7, 1940, under Serial No. 315,984.

What we claim is:

The combination with a deck mounted for vibratory movements, of apower-driven shaft mounted on said deck, a two-section vibrator headmounted on said shaft for rotation therewith, one of said sectionshaving an axially projecting hub and the other section being of annularform and mounted on said hub, said sec- JOSEPH A. COYLE. CHARLES H.ROTH.

